to connect arduino with ss-168 smoke detector

i want to connect smoke detector with arduino board . the problem is ss-168 smoke detector is not the sensor only . it contains buzzer and other circuit as its function to alarm. my concern is to use this detector and connect it to arduino, but i dont know which pin represent the output of this smoke detector so that i can connect it to arduino. i tried to see its datasheet but still it is not clear

I suggest you examine the circuit board and trace the circuit. If you post the resulting schematic, we may be able to work out that output the smoke sensor produces. Don't try to take the sensor head itself apart, it may contain radioactive material.